System and method for open-loop ultrasound therapy

ABSTRACT

A method for delivering ultrasound therapy using open-loop controls comprises inserting a distal tip of a therapeutic ultrasound applicator into a patient&#39;s urethra, the distal tip including an ultrasound transducer; acquiring ultrasound images of the patient&#39;s urethra and prostate with an ultrasound imaging probe; aligning the distal tip of the therapeutic ultrasound applicator with the patient&#39;s prostate using the ultrasound images; delivering therapeutic ultrasound energy to the patient&#39;s prostate, with the ultrasound transducer, according to a treatment plan, the treatment plan including a predetermined limited angular range for the therapeutic ultrasound energy that avoids the patient&#39;s rectum and neurovascular bundles, wherein the therapeutic ultrasound is delivered without temperature feedback data.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.62/882,662, filed Aug. 5, 2019, titled “Open-Loop Ultrasound Therapy,”which is hereby incorporated by reference.

TECHNICAL FIELD

This application relates generally to ultrasound therapy for medicalconditions.

BACKGROUND

Existing ultrasound treatment systems such as focused ultrasound therapyand surgery systems require or benefit from guidance, which can beprovided by ultrasound, magnetic resonance imaging (MRI) or othermethods. Guidance can assist the operator (human or machine) tospatially and/or temporally control the application of focusedultrasound to direct therapeutic thermal energy onto a desired (e.g.,diseased) target or region of interest.

MRI guidance is an expensive proposition, which requires placing apatient and MRI-compatible therapy equipment in special environments soas to monitor the therapy using MR thermometry methods. Specialized MRIradiologists are required to operate and monitor MRI-guided thermaltherapy facilities and procedures. In addition, since MRI guidancerequires immobilizing the patient (to avoid movement artefacts andinterference) MR-guided procedures can require general anesthesia of thepatient, which is another complicated and expensive undertaking. Suchoperations are not portable and are not accessible to sites that lackMRI facilities.

Certain procedures may be achieved without the need for high-precisionreal-time imaging such as MRI imaging, and less costly and moreaccessible solutions in thermal therapy such as ultrasound heat therapyare desirable.

SUMMARY

Example embodiments described herein have innovative features, no singleone of which is indispensable or solely responsible for their desirableattributes. The following description and drawings set forth certainillustrative implementations of the disclosure in detail, which areindicative of several exemplary ways in which the various principles ofthe disclosure may be carried out. The illustrative examples, however,are not exhaustive of the many possible embodiments of the disclosure.Without limiting the scope of the claims, some of the advantageousfeatures will now be summarized. Other objects, advantages and novelfeatures of the disclosure will be set forth in the following detaileddescription of the disclosure when considered in conjunction with thedrawings, which are intended to illustrate, not limit, the invention.

An aspect of the invention is directed to a method for deliveringultrasound therapy using open-loop controls. The method includesinserting a distal tip of a therapeutic ultrasound applicator into apatient's urethra, the distal tip including an ultrasound transducer;acquiring ultrasound images of the patient's urethra and prostate withan ultrasound imaging probe; aligning the distal tip of the therapeuticultrasound applicator with the patient's prostate using the ultrasoundimages; delivering therapeutic ultrasound energy to the patient'sprostate, with the ultrasound transducer, according to a treatment plan,the treatment plan including a predetermined limited angular range forthe therapeutic ultrasound energy that avoids the patient's rectum,neurovascular bundles, and internal organs other than the patient'sprostate. The therapeutic ultrasound is delivered without temperaturefeedback data.

In one or more embodiments, the method further comprises registering theultrasound images with a reference location on the therapeuticultrasound applicator to provide registered ultrasound images. In one ormore embodiments, the reference location comprises a fiducial mark. Inone or more embodiments, the method further comprises, in a computer,defining the treatment plan using the registered ultrasound images. Inone or more embodiments, defining the treatment plan includes setting apredetermined limited radial range for the therapeutic ultrasound energythat avoids a region immediately beyond the patient's prostate. In oneor more embodiments, defining the treatment plan includes setting apredetermined limited axial range for the therapeutic ultrasound energybetween a base and an apex of the patient's prostate.

In one or more embodiments, the predetermined limited angular rangecorresponds to an anterior direction in the patient. In one or moreembodiments, the predetermined limited angular range is 0° to 280°. Inone or more embodiments, the predetermined limited angular range is 0°to 240°, and 240° corresponds to the prostate's transition region.

In one or more embodiments, the method further comprises mechanicallycoupling the therapeutic ultrasound applicator to an ultrasoundapplicator positioning system. In one or more embodiments, the methodfurther comprises automatically aligning the distal tip of thetherapeutic ultrasound applicator with the patient's prostate using theultrasound applicator positioning system. In one or more embodiments,the method further comprises rotating the therapeutic ultrasoundapplicator, with the ultrasound applicator positioning system, over thepredetermined limited angular range while the therapeutic ultrasoundenergy is delivered.

In one or more embodiments, the method further comprises displaying theultrasound images on a display that is in electrical communication withthe ultrasound imaging probe. In one or more embodiments, the distal tipof the therapeutic ultrasound applicator includes a plurality ofultrasound transducers that are disposed about at least a portion of acircumference of the distal tip, and the method further comprisessimultaneously delivering therapeutic ultrasound energy to the patient'sprostate, with the ultrasound transducers, in multiple angulardirections. In one or more embodiments, the method further comprisesrotating the therapeutic ultrasound applicator so that the ultrasoundtransducers, in combination, are swept across the predetermined limitedangular range while simultaneously delivering therapeutic ultrasoundenergy to the patient's prostate in multiple angular directions.

In one or more embodiments, the therapeutic ultrasound is deliveredwithout MRI thermometry feedback data. In one or more embodiments, theultrasound imaging probe is integrated into the therapeutic ultrasoundapplicator.

Another aspect of the invention is directed to a system for open-loopultrasound therapy delivery. The system comprises a therapeuticultrasound applicator having a distal tip that includes an ultrasoundtransducer; an ultrasound imaging probe that acquires ultrasound imagesof the patient's urethra and prostate; an ultrasound applicatorpositioning system mechanically coupled to the therapeutic ultrasoundapplicator; a microprocessor-based UA positioning system controller inelectrical communication with the ultrasound applicator positioningsystem, the UA positioning system controller configured to adjust aposition and orientation of the ultrasound transducer to delivertherapeutic ultrasound energy to the patient's prostate according to atreatment plan; and a microprocessor-based computer in electricalcommunication with the therapeutic ultrasound applicator, the ultrasoundimaging probe, and the UA positioning system controller, the computerhaving a non-volatile memory that stores computer-readable instructionsthat, when executed by the microprocessor, cause the computer to:receive one or more inputs corresponding to the treatment plan, thetreatment plan including a predetermined limited angular range for thetherapeutic ultrasound energy that avoids the patient's rectum,neurovascular bundles, and internal organs other than the patient'sprostate, and generate control signals that cause the UA positioningsystem controller to rotate the ultrasound transducer over thepredetermined limited angular range and to simultaneously delivertherapeutic ultrasound energy from the ultrasound transducer over thepredetermined limited angular range. The therapeutic ultrasound isdelivered without temperature feedback data.

In one or more embodiments, the computer-readable instructions furthercause the computer to automatically register the ultrasound images witha reference location on the therapeutic ultrasound applicator. In one ormore embodiments, the reference location includes a fiducial mark.

In one or more embodiments, the treatment plan includes a predeterminedlimited radial range for the therapeutic ultrasound energy that avoids aregion immediately beyond the patient's prostate. In one or moreembodiments, the treatment plan includes a predetermined limited axialrange for the therapeutic ultrasound energy between a base and an apexof the patient's prostate. In one or more embodiments, the predeterminedlimited angular range corresponds to an anterior direction in thepatient. In one or more embodiments, the predetermined limited angularrange is 0° to 280°. In one or more embodiments, the predeterminedlimited angular range is 0° to 240°, and 0° and 240° correspond to theprostate's transition regions.

In one or more embodiments, the computer-readable instructions furthercause the computer to send a display output signal to a computer displayto display the ultrasound images. In one or more embodiments, the UApositioning system controller is further configured to automaticallyalign the distal tip of the therapeutic ultrasound applicator with theprostate using the ultrasound images. In one or more embodiments, theultrasound imaging probe is integrated into the therapeutic ultrasoundapplicator. In one or more embodiments, the computer-readableinstructions further cause the computer to determine a position of thetherapeutic ultrasound applicator relative to the patient's prostate.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the nature and advantages of the presentconcepts, reference is made to the detailed description of preferredembodiments and the accompanying drawings.

FIG. 1 is a block diagram of an open-loop ultrasound treatment systemaccording to one or more embodiments.

FIG. 2 is a side view of an example ultrasound applicator according toan embodiment.

FIG. 3 is a flow chart of a method for open-loop ultrasound therapyaccording to one or more embodiments.

FIG. 4 is a cross-sectional view of an example ultrasound applicator ina prostate according to an embodiment.

DETAILED DESCRIPTION

An open-loop ultrasound treatment system is used to deliver ultrasoundenergy to a target volume without MRI feedback information that istypically available in existing closed-loop ultrasound treatmentsystems. Specifically, in connection with ultrasound thermal therapy ofdiseased tissue volumes, e.g., diseased prostates, the present systemand method can be used to adequately provide conformal ultrasoundtherapy from an ultrasound applicator inserted into a patient's body.One application is the treatment of benign prostatic hyperplasia (BPH,also known as prostate enlargement), but other applications and targettissues are possible. Here, an elongated ultrasound applicator may beinserted into a patient's urethra and positioned approximately at asuitable location to deliver therapeutic ultrasound energy at or withinthe diseased volume. The ultrasound applicator includes a plurality ofelements, each providing a directional ultrasound beam, with thedirection of the beam adjustable by rotating the applicator.Additionally, cooling of non-diseased (especially critical or sensitive)tissues near the target volume can also be achieved in some aspects. Forexample, a rectal cooling device designed and operated to remove heatfrom the rectal wall and its vicinity may be operated in conjunctionwith the above treatment. In yet other aspects, ultrasound imaging ofthe regions at or near the treatment location can be used in one or moreembodiments.

The open-loop ultrasound treatment system includes an ultrasoundapplicator that is inserted transurethrally into the patient's prostate.The position of the ultrasound applicator can then be finely tuned,using an ultrasound applicator positioning system that can becomputer-controlled, to align the ultrasound transducer(s) on theinsertion end of the ultrasound applicator with the prostate. Forexample, an ultrasound imaging probe, such as a transrectal ultrasoundprobe and/or a transvesicle ultrasound probe, can generate ultrasoundimage data of the prostate and urethra, and the user can use theultrasound image data (e.g., depicted on a computer display) to director inform the user or the system as to how and where to apply andposition the ultrasound transducer(s) on the insertion end of theultrasound applicator to align the same with the prostate. In oneembodiment, the ultrasound applicator includes ultrasound fiducialmarkers so that the position of the ultrasound applicator can beunambiguously inferred from the ultrasound images obtained from theultrasound probe. In another embodiment, the ultrasound probe elementsare integrated directly into the ultrasound applicator and are used toimage the tissues surrounding the ultrasound applicator to determine itsposition with respect to the prostate.

In addition, the user can use the ultrasound image data, shown on acomputer screen, to create a treatment plan for ablating the prostate.The treatment plan can include parameters that define a treatment volumein the prostate. The parameters can include an axial component, a radialcomponent, and an angular-range component. The radial and angular-rangecomponents are defined in a plane that is orthogonal to the axis of theaxial component. Alternatively, the treatment plan can be an arbitraryvolume surrounding the urethra. The treatment plan is created so thatthe ultrasound applicator directs ultrasound energy generally in theanterior direction, away from the rectum, nerve bundles, and internalorgans other than the rectum, to increase patient safety.

The computer controls the ultrasound applicator according to thetreatment plan to insonify and ablate the treatment volume in theprostate. Control is achieved by modulating the acoustic power and theultrasound frequency emitted by each ultrasound element on theapplicator, and by continuously rotating the ultrasound applicator at anadjustable speed. Other parameters may be also controlled such as adriving frequency of the ultrasound transducers. During treatment, thecomputer can display ultrasound images (e.g., sagittal) collected by theultrasound imaging probe, which can be integrated into the ultrasoundapplicator. The computer can also display a progress indicator showingthe percentage of the treatment volume that has been insonified.

FIG. 1 is a block diagram of an open-loop ultrasound treatment system 10according to one or more embodiments. The system 10 includes anultrasound applicator (UA) 100, a UA positioning system 110, anultrasound imaging probe 120, and a system cart 130. The system cart 130includes a computer 132, a computer display 134, systems electronics140, and a fluid circulation system 150. The system cart 130 can includewheels or casters to facilitate portability.

An example of the UA 100 is described in U.S. Pat. No. 9,707,413, titled“Controllable Rotating Ultrasound Therapy Applicator,” issued on Jul.18, 2017, which is hereby incorporated by reference. An example of theUA positioning system 110 is disclosed in U.S. patent application Ser.No. 16/248,246, titled “Therapeutic Applicator Positioning System WithPassive and Active Positioning,” filed on Jan. 15, 2019, which is herebyincorporated by reference.

The computer 132 includes a hardware-based microprocessor, memory thatis operatively coupled to the microprocessor, network ports, I/O ports,a graphics processor, and other components. The memory includesnon-volatile memory that stores computer-readable instructions (e.g.,software) that can be executed by the microprocessor to perform one ormore operations, functions, and/or tasks.

The systems electronics 140 include an RF power controller 142 thatgenerates driving signals for powering the UA 100 at a desired frequencyand amplitude (power). The driving signals are sent to the UA 100 viaone or more RF cables 105. An example of the RF power control unit isdisclosed in U.S. Pat. No. 9,931,523, titled “RF Power Controller forUltrasound Therapy System,” issued on Apr. 3, 2018, which is herebyincorporated by reference. The UA 100 can be used to perform ultrasoundtherapy on a target volume in a patient 160, who may be in a supineposition on a patient support 170. In one example, the target volumecorresponds to a tumor and the ultrasound therapy includes generatingsufficient energy, using ultrasound energy, to ablate the tumor.

The systems electronics 140 also include a UA positioning systemcontroller 144 that generates optional motion control signals for the UApositioning system 110 to align the UA 100 with the prostate. The motioncontrol signals can be based, at least in part, on image data outputtedfrom the ultrasound imaging probe 120. The ultrasound imaging probe 120can be a transrectal ultrasound (TRUS) probe, a transvesicle ultrasoundprobe, a probe integrated into the UA, or another ultrasound imagingprobe. Data representing ultrasound images is sent from the ultrasoundimaging probe 120 to the computer 132 which can optionally render anddisplay the ultrasound images on display 134.

The fluid circulation system 150 recirculates cooling fluid (e.g.,water) to the UA 100. The fluid circulation system 150 includes a fluidcirculation pump and a cooling unit (e.g., a chiller, heat exchanger,etc.) to circulate the cooling fluid between (a) the UA 100 to cool theUA 100 during operation and (b) the cooling unit where the heatedcooling fluid is cooled to a predetermined temperature set point, suchas room temperature or another temperature. The fluid circulation pumpcan be a peristaltic pump or another pump A tube set 108 can fluidlycouple the UA 100 and the fluid circulation system 150. In someembodiments, the fluid circulation system 150 includes a degasser thatremoves air bubbles from the cooling fluid.

The computer 132 is in electrical communication (e.g., via wired and/orwireless connections) with the system electronics 140 and the fluidcirculation system 150. Through the electrical connection, the computer132 can send control signals to any of the system electronics 140 or thefluid circulation system 150 and can receive data or other informationfrom any of the system electronics 140 or the fluid circulation system150. For example, the computer 132 can send RF power control signals tothe RF controller 142 that cause the RF controller 142 to generatedriving signals having a frequency and amplitude for powering the UA 100according to a treatment plan. In addition, the computer 132 can send UAposition control signals that cause the UA position controller 144 toadjust the UA positioning system 110 to set the position, orientation,and/or rotation of the UA 100, such as according to a treatment plan.Further, the computer 132 can send fluid circulation control signals tothe fluid circulation system 150 to set the temperature set point of thecooling fluid and/or to set the speed of the fluid circulation pump.

The computer 132 can also receive feedback data or other informationfrom the system electronics 140 and/or the fluid circulation system 150.For example, the RF controller 142 can send the actual RF power of thedriving signals to the computer 132, and the computer 132 can make anyadjustments on the RF power control signals as needed. Similarly, the UAposition controller 144 can send the actual position, orientation,and/or rotation of the UA positioning system 110 to the computer 132,and the computer 132 can make any adjustments on the UA position controlsignals as needed. Further, the fluid circulation system 150 can sendthe actual temperature of the cooling fluid and/or the actual speed ofthe fluid circulation pump to the computer 132, and the computer 132 canmake any adjustments on the fluid circulation control signals as needed.The computer 132 can also be in electrical communication with otherdevices or instruments that can independently monitor these componentsand provide independent feedback data. For example, an RF detector canmonitor the driving signals generated by the RF controller 142 andprovide feedback data to the RF controller 142 and/or to the computer132. Similarly, a thermocouple can monitor the temperature of thecooling fluid and provide feedback data to the chiller and/or to thecomputer 132.

The computer 132 also receives ultrasound image data from the ultrasoundimaging probe 120, which the computer 132 can use as feedback data toadjust the UA position control signals. The computer 132 can also usethe ultrasound image data to align (e.g., automatically align) thedistal tip of the UA 100 with the prostate and to register (e.g.,automatically register) one or more reference locations on the UA 100with the ultrasound images. For example, the UA 100 can include one ormore fiducial marks that is/are opaque to ultrasound and, thus, visiblein the ultrasound images. In addition, the shaft of the UA 100 caninclude two or more fiducial marks disposed along a reference line thatis parallel to the longitudinal axis of the shaft. The computer 132 candetermine the reference line by detecting the relative positions of thefiducial marks, using the ultrasound images, and can infer other aspectsof the UA 100 based on their relationship to the reference line. Thememory of computer 132 can have information regarding the relationshipbetween the fiducial marks and other portions of the UA 100, such as thedistance between the fiducial marks and other portions of the UA 100.

Alternatively, the ultrasound imaging probe 120 and the UA 100 can beintegrated together as a single unit. In this embodiment, the ultrasoundimaging probe 120 can acquire images of the surrounding tissues and/oranatomical structures. Software running on the computer 132 candetermine the relative position of the integrated UA/imaging probe withrespect to the prostate based on these images, such as through imagerecognition, machine learning, and/or other techniques, to achieve imageregistration and prostate alignment.

FIG. 2 is a side view of an example ultrasound applicator 20 accordingto an embodiment. The ultrasound applicator 20 includes a shaft 210 thatconnects a handle 220 to a distal tip 230. One or more ultrasoundtransducers is/are disposed on the distal tip 230. A proximal end 240 ofthe ultrasound applicator 20 includes electrical connections that forreceiving driving signals from an ultrasound controller, such as RFpower controller 142. In addition, the proximal end includes inlet andoutlet fluid couplings that can be fluidly coupled to a fluidcirculation system (e.g., fluid circulation system 150) to circulation acooling fluid within the ultrasound applicator 20. The ultrasoundapplicator 20 can be the same as or different than UA 100. In someembodiments, the ultrasound applicator 20 includes one or moreultrasound imaging elements 250 that acquire images of the surroundingtissues and/or anatomical structures to determine the relative locationof the ultrasound applicator 20 with respect to the prostate.

FIG. 3 is a flow chart 30 of a method for open-loop ultrasound therapyaccording to one or more embodiments. The system 10 can be used toperform one or more steps of flow chart 30. The method is performedusing open-loop process controls without using temperature feedback data(e.g., MRI thermometry data).

In step 300, a patient lies (e.g., in a supine position) on an operatingbed (e.g., patient support 170) or other working surface. The patient(e.g., patient 160) can be sedated before the procedure starts. In step310, a medical clinician or technician inserts the distal tip of the UA100 transurethrally into the patient's prostate. The distal tip of theUA 100 includes one or more ultrasound transducers that can generatetherapeutic ultrasound energy. In step 220, the UA 100 is mechanicallycoupled to (e.g., mounted on) the UA positioning system 110. In someembodiments, step 320 can occur prior to step 310.

In step 330, the ultrasound imaging probe 120 is used to acquireultrasound images of the prostate, urethra, and surrounding anatomy. Theacquired ultrasound images can include multi-slice ultrasound images(e.g., a plurality of cross-sectional ultrasound images) orthree-dimensional ultrasound images. Ultrasound image data representingthe acquired ultrasound images are sent from the ultrasound imagingprobe 120 to the computer 132. The computer 132 can optionally displaythe ultrasound images on the computer display 134. As discussed above,the ultrasound imaging probe 120 and the UA 100 can be integratedtogether as a single unit.

In step 340, the clinical operator remotely controls the UA 100 (e.g.,by controlling the UA positioning system 110) to align the distal tip ofthe UA 100 with the prostate. The alignment can be based on theultrasound images acquired and displayed in step 330 which can be usedfor visual feedback for the clinical operator. Alternatively, thecomputer 132 can use the ultrasound images to automatically align thedistal tip of the UA 100 with the prostate by sending appropriate UAposition control signals to the UA position controller 144. The computer132 can use image recognition or machine learning to determine whetherthe distal tip of the UA 100 and the prostate are aligned and togenerate UA position control signals to align the distal tip of the UA100 and the prostate. Alternatively, when the imaging probe 120 isintegrated into the UA 100, the computer 132 can use images acquired bythe imaging probe 120 to determine how far to move the UA 100 to achieveregistration to the prostate. Steps 330 and 340 can be performedsimultaneously.

In step 350, the computer 132 registers the image(s) of the prostatewith one or more reference locations (e.g., frames of reference) on theUA 100, such as one or more fiducial marks. For example, a fiducial markcan be located at a predetermined distance from the distal tip of the UA100. The computer 132 can automatically locate the fiducial marks or thefiducial marks can be manually identified using the computer 132.Alternatively, the computer 132 can register the images with respect tothe UA 100 which includes the imaging probe 120.

Using the registered image(s), the clinical operator defines a treatmentplan for the ultrasound therapy using the computer 132 at step 360. Thetreatment plan can include the radial, axial, and angular-rangecoordinates of the ultrasound therapy (e.g., ablation), which defines atarget volume. The radial and/or the angular-range coordinates can varyas a function of the axial position. In some embodiments, the angularrange can include an angular range of 0° up to about 280° including upto about 240°, which can correspond to the prostate's transition region(e.g., as illustrated in FIG. 4). The axial position can cover theregion extending from the base of the prostate to some point close tothe apex of the prostate. The radial coordinates are preferablyconfigured to avoid the region beyond the prostate capsule. In general,the coordinates of the target volume are selected to avoidanatomically-sensitive areas such as the patient's neurovascularbundles, rectum, and internal organs other than the prostate. Forexample, the angular range coordinates can correspond to the anteriordirection in the patient and/or the anterior and lateral directions inthe patient, to avoid the patient's neurovascular bundles, rectum, andinternal organs other than the prostate.

FIG. 4 is a cross-sectional view of an example ultrasound applicator 400in a prostate 410 according to an embodiment. The treatment plan definesthe treatment volume 420 such that the angular-range coordinates avoidthe patient's neurovascular bundles 430 and rectum 440, which aregenerally in a posterior direction with respect to the ultrasoundapplicator 400. For example, the angular-range coordinates can include0° (e.g., the left lateral side in FIG. 4) up to 180° (the right lateralside in FIG. 4). Alternatively, the angular-range coordinates caninclude 0° up to 240° where a 0° radial line 422 intersects the lefttransition region 412 and a 240° radial line 424 intersects the righttransition region 414. In general, the angular-range coordinatescorrespond to lateral and/or anterior directions in the patient withrespect to the ultrasound applicator 400. The angular-range coordinatescan also avoid internal organs other than the prostate. Ultrasoundapplicator 400 can be the same as or different than ultrasoundapplicator 20 and UA 100.

Returning to FIG. 3, in step 370, the UA 100 delivers ultrasound energyaccording to the treatment plan using open-loop controls that do notinclude temperature-feedback data. The ablation occurs in the generalanterior and/or lateral directions, with respect to UA 100, away fromanatomically-sensitive areas such as the patient's neurovascular bundlesand rectum (e.g., as illustrated in FIG. 4) and internal organs otherthan the prostate , which can increase the safety of the procedure. Theultrasound energy is delivered in an open-loop fashion (e.g., withouttemperature feedback such as MRI thermometry feedback), with the powerlevels and the rotation rate of the UA 100 controlled by softwarerunning in the computer 132. The UA 100 can be rotated by the UApositioning system 110. In an alternative embodiment, the UA 100 caninclude a plurality of transducers disposed about at least a portion ofthe circumference of the distal end of the UA 100. The transducers canbe operated to direct ultrasound energy simultaneously in multipleangular directions, which can reduce treatment time as opposed torotating the UA 100 over the full angular range of the target volume.

In step 380, the computer 132 optionally displays the ultrasound imageson display 134. The ultrasound images (e.g., sagittal planar images) canbe displayed using ultrasound image data collected by the ultrasoundimaging probe 120. The computer 132 can also display a progressindicator showing the completion percentage of the procedure. In someembodiments, the computer 132 can overlay the treatment volume on theultrasound images. Additional or other images can also be displayed.Step 380 can occur simultaneously with any of steps 330, 340, 350, 360,and/or 370.

In an aspect, the present system and method allows for cost-effectiveand clinically-adequate treatment of some conditions such as prostateenlargement using ultrasound energy directed by one or more ultrasoundtransducers in a suitable probe where the procedure is controlled in anopen-loop fashion and without the need for MRI imaging. In someembodiments, the ultrasound transducers can comprise an ultrasoundtransducer array, which can be controlled (e.g., phase-controlled) tofocus ultrasound and/or electronically steer the ultrasound. In one ormore examples, a multi-slice image may be employed to inform a method,system or clinical operator on details of delivering a treatment. Thetreatment can include a plan involving a radial and/or axial spatialrange for treatment.

Specifically, and in some aspects, an ultrasound therapy applicator canbe inserted into the male urethra in combination with a trans-rectalultrasound imaging probe for therapy applicator positioning andmonitoring. In yet other aspects, the invention provides for continuousor substantially continuous treatment in combination with an open-looptreatment algorithm and treatment plan including appropriate treatmentparameters, which in turn can include a rate of rotation of a therapyapplicator about an axis thereof, a power level of one or moreultrasonic energy sources, and so on.

Auxiliary features of the invention can also include controlled coolingwater circulation in a therapy device or location so as to control orreduce unwanted heat from accumulating therein. Sterile fluids such aswater can be circulated in said device or location through a tube setusing a peristaltic pump or other fluid driver. Cooling of atransurethral applicator and/or cooling of tissue using a rectal coolingdevice are possible implementations in some embodiments.

Another advantage of the systems and methods disclosed herein is thereduced cost of the procedure. This is the result of the reducedtreatment time and the ability to conduct the procedure without using anMRI system.

The present invention should not be considered limited to the particularembodiments described above. Various modifications, equivalentprocesses, as well as numerous structures to which the present inventionmay be applicable, will be readily apparent to those skilled in the artto which the present invention is directed upon review of the presentdisclosure. The above-described embodiments may be implemented innumerous ways. One or more aspects and embodiments involving theperformance of processes or methods may utilize program instructionsexecutable by a device (e.g., a computer, a processor, or other device)to perform, or control performance of, the processes or methods.

In this respect, various inventive concepts may be embodied as anon-transitory computer readable storage medium (or multiplenon-transitory computer readable storage media) (e.g., a computer memoryof any suitable type including transitory or non-transitory digitalstorage units, circuit configurations in field-programmable gate arrays(FPGAs) or other semiconductor devices, or other tangible computerstorage medium) encoded with one or more programs that, when executed onone or more computers or other processors, perform methods thatimplement one or more of the various embodiments described above. Whenimplemented in software (e.g., as an application or “app”), the softwarecode may be executed on any suitable processor or collection ofprocessors, whether provided in a single computer or distributed amongmultiple computers.

Further, it should be appreciated that a computer may be embodied in anyof a number of forms, such as a rack-mounted computer, a desktopcomputer, a laptop computer, or a tablet computer, as non-limitingexamples. Additionally, a computer may be embedded in a device notgenerally regarded as a computer but with suitable processingcapabilities, including a personal digital assistant (PDA), asmartphone, or any other suitable portable or fixed electronic device.

Also, a computer may have one or more communication devices, which maybe used to interconnect the computer to one or more other devices and/orsystems, such as, for example, one or more networks in any suitableform. The networks can include a local area network, a wide areanetwork, an enterprise network, an intelligent network (IN), a cellularnetwork, a WiFi network, a virtual private network, or the Internet.Such networks may be based on any suitable technology and may operateaccording to any suitable protocol and may include wireless networksand/or wired networks.

Also, a computer may have one or more input devices and/or one or moreoutput devices. These devices can be used, among other things, topresent and/or manipulate a user interface. Examples of output devicesthat may be used to provide a user interface include printers or displayscreens for visual presentation of output and speakers or other soundgenerating devices for audible presentation of output. Examples of inputdevices that may be used to manipulate or interact with a user interfaceinclude keyboards, and pointing devices, such as mice, touch pads, anddigitizing tablets. As another example, a computer may receive inputinformation through speech recognition or in other audible formats.

The non-transitory computer readable medium or media may betransportable, such that the program or programs stored thereon may beloaded onto one or more different computers or other processors toimplement various one or more of the aspects described above. In someembodiments, computer readable media may be non-transitory media.

The terms “program,” “app,” and “software” are used herein in a genericsense to refer to any type of computer code or set ofcomputer-executable instructions that may be employed to program acomputer or other processor to implement various aspects as describedabove. Additionally, it should be appreciated that, according to oneaspect, one or more computer programs that when executed perform methodsof the present application need not reside on a single computer orprocessor, but may be distributed in a modular fashion among a number ofdifferent computers or processors to implement various aspects of thepresent application.

Computer-executable instructions may be in many forms, such as programmodules, executed by one or more computers or other devices. Generally,program modules include routines, programs, objects, components, datastructures, etc. that performs particular tasks or implement particularabstract data types. The functionality of the program modules may becombined or distributed as desired in various embodiments.

Also, data structures may be stored in computer-readable media in anysuitable form. For simplicity of illustration, data structures may beshown to have fields that are related through location in the datastructure. Such relationships may likewise be achieved by assigningstorage for the fields with locations in a computer-readable medium thatconvey relationship between the fields. However, any suitable mechanismmay be used to establish a relationship between information in fields ofa data structure, including through the use of pointers, tags or othermechanisms that establish relationship between data elements.

Thus, the present disclosure and claims include new and novelimprovements to existing methods and technologies, which were notpreviously known nor implemented to achieve the useful results describedabove. Users of the present method and system will reap tangiblebenefits from the functions now made possible on account of the specificmodifications described herein causing the effects in the system and itsoutputs to its users. It is expected that significantly improvedoperations can be achieved upon implementation of the claimed invention,using the technical components recited herein.

Also, as described, some aspects may be embodied as one or more methods.The acts performed as part of the method may be ordered in any suitableway unless stated otherwise. Accordingly, embodiments may be constructedin which acts are performed in an order different than illustrated,which may include performing some acts simultaneously, even though shownas sequential acts in illustrative embodiments.

What is claimed is:
 1. A method for delivering ultrasound therapy usingopen-loop controls, comprising: inserting a distal tip of a therapeuticultrasound applicator into a patient's urethra, the distal tip includingan ultrasound transducer; acquiring ultrasound images of the patient'surethra and prostate with an ultrasound imaging probe; aligning thedistal tip of the therapeutic ultrasound applicator with the patient'sprostate using the ultrasound images; delivering therapeutic ultrasoundenergy to the patient's prostate, with the ultrasound transducer,according to a treatment plan, the treatment plan including apredetermined limited angular range for the therapeutic ultrasoundenergy that avoids the patient's rectum, neurovascular bundles, andinternal organs other than the patient's prostate; wherein thetherapeutic ultrasound is delivered without temperature feedback data.2. The method of claim 1, further comprising registering the ultrasoundimages with a reference location on the therapeutic ultrasoundapplicator to provide registered ultrasound images.
 3. The method ofclaim 2, wherein the reference location comprises a fiducial mark. 4.The method of claim 2, further comprising, in a computer, defining thetreatment plan using the registered ultrasound images.
 5. The method ofclaim 4, wherein defining the treatment plan includes setting apredetermined limited radial range for the therapeutic ultrasound energythat avoids a region immediately beyond the patient's prostate.
 6. Themethod of claim 5, wherein defining the treatment plan includes settinga predetermined limited axial range for the therapeutic ultrasoundenergy between a base and an apex of the patient's prostate.
 7. Themethod of claim 1, wherein the predetermined limited angular rangecorresponds to an anterior direction in the patient.
 8. The method ofclaim 1, wherein the predetermined limited angular range is 0° to 280°.9. The method of claim 8, wherein: the predetermined limited angularrange is 0° to 240°, and 240° corresponds to the prostate's transitionregion.
 10. The method of claim 1, further comprising mechanicallycoupling the therapeutic ultrasound applicator to an ultrasoundapplicator positioning system.
 11. The method of claim 10, furthercomprising automatically aligning the distal tip of the therapeuticultrasound applicator with the patient's prostate using the ultrasoundapplicator positioning system.
 12. The method of claim 10, furthercomprising rotating the therapeutic ultrasound applicator, with theultrasound applicator positioning system, over the predetermined limitedangular range while the therapeutic ultrasound energy is delivered. 13.The method of claim 1, further comprising displaying the ultrasoundimages on a display that is in electrical communication with theultrasound imaging probe.
 14. The method of claim 1, wherein the distaltip of the therapeutic ultrasound applicator includes a plurality ofultrasound transducers that are disposed about at least a portion of acircumference of the distal tip, and the method further comprisessimultaneously delivering therapeutic ultrasound energy to the patient'sprostate, with the ultrasound transducers, in multiple angulardirections.
 15. The method of claim 14, further comprising rotating thetherapeutic ultrasound applicator so that the ultrasound transducers, incombination, are swept across the predetermined limited angular rangewhile simultaneously delivering therapeutic ultrasound energy to thepatient's prostate in multiple angular directions.
 16. The method ofclaim 1, wherein the therapeutic ultrasound is delivered without MRIthermometry feedback data.
 17. The method of claim 1, wherein theultrasound imaging probe is integrated into the therapeutic ultrasoundapplicator.
 18. A system for open-loop ultrasound therapy delivery,comprising: a therapeutic ultrasound applicator having a distal tip thatincludes an ultrasound transducer; an ultrasound imaging probe thatacquires ultrasound images of the patient's urethra and prostate; anultrasound applicator positioning system mechanically coupled to thetherapeutic ultrasound applicator; a microprocessor-based UA positioningsystem controller in electrical communication with the ultrasoundapplicator positioning system, the UA positioning system controllerconfigured to adjust a position and orientation of the ultrasoundtransducer to deliver therapeutic ultrasound energy to the patient'sprostate according to a treatment plan; and a microprocessor-basedcomputer in electrical communication with the therapeutic ultrasoundapplicator, the ultrasound imaging probe, and the UA positioning systemcontroller, the computer having a non-volatile memory that storescomputer-readable instructions that, when executed by themicroprocessor, cause the computer to: receive one or more inputscorresponding to the treatment plan, the treatment plan including apredetermined limited angular range for the therapeutic ultrasoundenergy that avoids the patient's rectum, neurovascular bundles, andinternal organs other than the patient's prostate, and generate controlsignals that cause the UA positioning system controller to rotate theultrasound transducer over the predetermined limited angular range andto simultaneously deliver therapeutic ultrasound energy from theultrasound transducer over the predetermined limited angular range,wherein the therapeutic ultrasound is delivered without temperaturefeedback data.
 19. The system of claim 18, wherein the computer-readableinstructions further cause the computer to automatically register theultrasound images with a reference location on the therapeuticultrasound applicator.
 20. The system of claim 19, wherein the referencelocation includes a fiducial mark.
 21. The system of claim 18, whereinthe treatment plan includes a predetermined limited radial range for thetherapeutic ultrasound energy that avoids a region immediately beyondthe patient's prostate.
 22. The system of claim 21, wherein thetreatment plan includes a predetermined limited axial range for thetherapeutic ultrasound energy between a base and an apex of thepatient's prostate.
 23. The system of claim 18, wherein thepredetermined limited angular range corresponds to an anterior directionin the patient.
 24. The system of claim 18, wherein the predeterminedlimited angular range is 0° to 280°.
 25. The system of claim 24,wherein: the predetermined limited angular range is 0° to 240°, and 0°and 240° correspond to the prostate's transition regions.
 26. The systemof claim 18, wherein the computer-readable instructions further causethe computer to send a display output signal to a computer display todisplay the ultrasound images.
 27. The system of claim 18, wherein theUA positioning system controller is further configured to automaticallyalign the distal tip of the therapeutic ultrasound applicator with theprostate using the ultrasound images.
 28. The system of claim 18,wherein the ultrasound imaging probe is integrated into the therapeuticultrasound applicator.
 29. The system of claim 28, wherein thecomputer-readable instructions further cause the computer to determine aposition of the therapeutic ultrasound applicator relative to thepatient's prostate.